Thank you for the link EGBKFLYER. I'm sure that more than a few instructors will find it useful.
You are of course right when you say that the "very low margins in GA training makes things difficult". I guess that this is really the route of the problem.
To end I would just like to say that my aim throughout this thread has been to try and say that instructing can be a rewarding career. Both financially and personally. I just thought that it would be nice to see a bit of positive feed back for a change.